Can rationality alone cure suicidal depression?
If so, what steps would it take for one to commit oneself fully to reason, when one is in a perpetual state of suffering?
If you are talking about yourself, and it is serious enough to think about suicide, then I think you ought to think through your reasons very carefully, since there is no turning back from suicide once it is done. Definitely talk to a psychotherapist (for talking and finding the problem) or a psychiatrist (for any medical drug needs).
But as to the question of will Objectivism or being rational cure your depression – the answer is yes and no. Being rational, which Objectivism can help you accomplish, will give you more to live for, so long as you don’t focus too much on the irrational things going on that you don’t have any control over. But I have to agree with others about the role of introspection (with or without a psychotherapist) in identifying what the conflicts are that lead you to believe that you cannot accomplish anything, or cannot go beyond what you have already accomplished.
But, in confronting my own personal problems, I have found that introspection alone is not sufficient. Fundamentally, psychological problems stem from two sources: 1) conflicts in the subconscious; and 2) an improper relationship between your mind and existence (on both the conscious and subconscious level).
Objectivism will definitely help you resolve conflicts or contradictions in your conscious mind. It may take a while, but by thinking things through, your conscious mind will be better in tuned with reality with Objectivism as your guide, and you will be much more open to achieving your own happiness.
The subconscious is a little different in that you do not have direct volitional control of your subconscious. That is, if you are feeling down and out about things in general, studying Objectivism will definitely help, and the subconscious will follow through by you making integrations in tuned with reality, for the most part; but you may still have things nagging you in your subconscious that you are not going to be able to resolve merely by thinking about them. Introspection is important, but to fully resolve conflicts in the subconscious you have to set about to take rational actions that may be counter to your subconscious.
For example, if you are down and out and clinically depressed, get professional help, but staying just in your own mind is not going to bring about a solution. You have to get up and pursue values instead of sitting around the house and moping about how bad things are. This might require you acting against subconscious urges to just stay put and do nothing all day long.
In other words, your subconscious needs real pursuit of real values, not just imagining them or reading about them in a novel, in order to have a proper relationship to reality. For example, let’s say you read a novel about someone doing something that you would really like to do, but you are depressed so you don’t do it. Your subconscious will add that up to effectively saying that you are not worthy of pursuing that value, if you don’t actually pursue it. Your conscious mind says it would be great to try, but by not doing it your subconscious will be set to not do it even against a conscious will to give it a try.
So, don’t go by your emotions. Rationally consider a value you want to pursue and then go pursue it, even if you don’t “feel like it.” Act according to reason, rather than emotion. Sometimes this can be very difficult, but it is the only effective way of re-writing the subconscious.